In the making of chemical immunoassay tests with microtiter pieces or sticks, many filling, emptying and washing procedures are performed that are time consuming. Prior microtiter pieces have had deep wells with cylindrical vertical side walls that have taken time to fill and are difficult to empty and clean. Expensive devices have been required to separately fill and empty the individual deep wells with reagents and specimens and the tasks have been cumbersome and tedious. Accurate tests have not resulted from using these deep well pieces because full intimate contact of the fluids upon wall surfaces of deep wells of clear plastic do not result and since there is optical interference between adjacent wells of the piece, good test and reliable readings have not always been determined.
According to the present invention, a microtiter stick is produced in the form of an elongated, molded, polystyrene strip, with a series of evenly linearly-spaced, shallow wells for receiving the fluids to be tested. A lens is located in the bottom and the stick has a handle extending from one end by which the stick can be grasped. When the wells are to be emptied, the stick is taken by its handle and, by a snap of the wrist, the wells are easily and quickly emptied all at one time.
A raised border on the top surface surrounds the wells and permits all the wells to be easily filled together by simply flooding the top surface area about the wells with fluid. Both the filling and emptying of the wells is done without the need for expensive filling and decantation equipment.
The well lens bottom portions are transparent while the well walls are frosted or stippled to eliminate optical color interference between adjacent wells and to increase, in effect, the available work surface area versus smooth optical surface at the well interior.
Bottom lens portions formed in the flat bottom surface of the stick are recessed to keep them from being scratched when the sticks are rested or slid upon a supporting surface. Further, these sticks are disposable with the completion of any one test.
It is the principal object of the present invention to provide a chemical immunoassay test stick with a most favorably shaped and finished surface test well for residue and color analysis of the fluids being tested.
It is another object of the invention to provide an immunoassay test stick having a series of shallow-bottomed lens wells that are shaped for effecting rapid, convenient, and accurate performance of immunoassay tests.
It is another object of the invention to provide an immunoassay test well stick with a handle extension by which the stick can be grasped and flipped with but a snap of the wrist thereby emptying all wells of their test fluids at one time and done without the need of expensive liquid decantation apparatus.
It is still another object of the invention to provide an immunoassay test stick in which optical interference between test wells is eliminated so that more accurate readings will be obtained.
It is further object of the invention to provide an immunoassay test stick in which all of the test wells can be filled with specimens or reagents at one time by simply flooding the top surface of the stick about the well openings.
It is a further object of the invention to provide an immunoassay test stick in which the full interior wall surface of the well is available for immobilizing the antigens or antibodies.
It is a still further object of the invention to provide a immunoassay test stick that does not require any tray or rack for its support and that may be rested with safety upon any flat surface.
Briefly, present immunoassay test stick has a series of optically-shaped and frosted test wells, except for their lens portions, and a handle by which the stick can be picked up to empty the wells of their test fluids. The top surface of the stick has a boundary border around the wells so that all of the wells can be filled at once by a controlled flooding of the top surface area.
One big advantage of the present stick is that it is convenient to use and requires little or no instrumentation to fill and empty in the performance of the immunoassay tests. A further advantage is that maximum capacity of each well is but 100 milliliters and automatic measured dispensing is easily achieved in one step by simply flooding the wells within boundary area with the test fluids.
For a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing. Summary of the Invention
The invention resides in a microtiter stick for use in performing immunochemical tests such as determining the extent of the allergy content of a blood specimen by chemical treatment of the specimen. The stick comprises a transparent plastic-like body having an affinity for protein. The body is elongated and has a flat top surface with a plurality of small shallow wells in the surface. The wells are aligned in a series along the body in close proximity to one another. Each of the wells is a truncated hemisphere and has an optically clear, circular, concave surface and the remainder is frosted or stippled to lessen color interference between wells and to improve its surface for the bonding of protein and chemical residues to the surface.
A handle projects from one end of the body portion of the stick by which the stick may be grasped and flipped to empty the wells of their contents when the tests have been performed. The body has a flat bottom supporting surface and is recessed to form portions of the lenses of the well. These lens portions are spaced from the flat bottom to protect the lens portions from being scratched when the stick is placed on a supporting surface. They are flat, clear, transparent and each optically aligned with a concave lens surface to produce between them a planar-concave reducing lens.
The upper surface of the body of the stick has a boundary border in the form of a wall surrounding the flat top surface, the wall being located in close proximity to the well openings to create a resevoir so that the wells may be simulataneously filled by controlled flooding of the top surface with specimen or reagents used in testing.
The stick is of a length sufficient to span the sides of a standard tray and has an extension at one end of accomodate an upstanding small projection at one side of the tray with the handle extending from the opposite side of the body of the stick over the opposite side of the tray. The body of the stick is notched at the end opposite the handle to accomodate spaced inwardly extending projections of the opposite side of the tray while the handle portion is rested thereon.
The above and other features of the invention included various novel details of construction and combinations of parts will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular microtiter stick embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in varied and numerous embodiments without departing from the scope of the invention.